It has long been known that the action of the heart depends upon electrical signals carried along the surface of the heart tissue. Sometimes these electrical signals become faulty. It has been found that ablating (burning) these cardiac conduction pathways in the region of the problem destroys the tissue to eliminate the faulty signal. Electrophysiology (EP) catheters are catheters having one or more electrodes at their tips and are used for both diagnosis and therapy. The electrodes at their tips of EP catheters allow the physician to measure electrical signals along the surface of the heart (called mapping) and then, when necessary, ablate certain tissue using, typically, radio frequency (RF) energy directed to one or more high energy capable ablation electrodes.